Paper-machine oils



United States Patent PAPER-MACHINE OILS John N. Bowden, Crystal Lake, and Elmer W. Brennan,

Carpentersville, 111., assignors to The Pure Di] Company, Chicago, 111., a corporation of Ohio No Drawing. Application December 28, 1955 Serial No. 555,749

6 Claims. (Cl. 252-32.7)

This invention relates to paper-machine oils and, more particularly, to paper-machine oil compositions possessing lubrication and oxidation resistance properties, and additional unexpected attributes of good demulsibility and high resistance to additive leaching, especially under the adverse contamination, pressure and temperature conditions found in modern, paper machine, lubricating systems.

Modern Fourdrinier and cylinder or vat type paper machines require special lubricants and rather complex lubricating systems for the proper protection of fastmoving parts operating on plain, sleeve, roller and ball bearings, and employing both chain and gear drives. Lubrication is of great importance from the standpoint of preserving the expensive machinery 'and allowing maximum production of uniform quality paper. Proper lubrication assures continuity of operation, reduction in maintenance costs, decreased oil consumption, and safe operation at high speeds and temperatures to maintain uniform production of high quality papers. Lubrication at the so-called wet end of the machines is afiected by the type of bearings, contamination by water or paper pulp, temperature, and the method of lubricant application. Lubrication at the dryer section of the machine is affected, in addition, by such factors as oil contamination by moisture or dust, and high bearing temperatures and pressures. A paper-machine oil may be applied by wick-feed oiling, by oil circulation, by full-pressure lubrication or by gravity feed. The paper-machine oil is subjected to various processes including filtration, cooling, centrifugal purificaiton, forced circulation and storage. The oil both during use and storage must be capable of dispersing paper dust and moisture to hold same in a dispersed state so that they may be removed from the bearings and lines, and conveyed to a settling tank and filters for separation from the oil. These oils must, in addition to performing their functions as extremely durable lubricants, possess a certain amount of detergency and resistance to oxidation, and furthermore, should prevent the rusting of metal parts. The paper-machine oils used today must exhlbit a preferential wetting property for metal surfaces in the presence of water and dissolved chemicals while at the same time resisting lealcage, which may contaminate the paper stock, and resisting leaching of the various addends therefrom by contact with steam and hot water.

The drum dryer units of paper machines are heated with steam to temperatures that may reach 350 F., and the roller bearings and journals in these units are subjected to unusually severe temperature and pressure conditions. The individual paper rolls commonly weigh as much-as 18 tons, requiring extreme pressure lubricants and the. use ofv circulating oil systems. To be satisfactory under these conditions, lubricants must meet the additional requirements of rust inhibition and easy demulsibility imposed by the unavoidable leakage of steam, water, and other contaminants into the lubricating system. Ordinarily, condensed steam so introduced into the lubricant is allowed to settle out of the oil in the storage-settling reservoir, from which it is periodically or continuously Withdrawn. A problem is involved in this settling and withdrawal, however, since small amounts of oil are usually held in the separated water phase and are lost when the water is withdrawn and discarded. There is also a tendency for varying amounts of water to remain in the oil being circulated, which adversely affects the performance of the lubricant. Still another problem arises from the introduction and separation of water, since in separating the oil therefrom, the water commonly removes or carries with it in dissolved or suspended form significant amounts of important additives essential to the high level of performance of the lubricant. The magnitude and rate of additive leaching normally tends to increase with increasing temperatures of operation of the machinery necessitated by operations at maximum capacity to meet current high production schedules. These and related problems in paper-machine oils are discussed in the articles entitled, Lubricating the Modern Paper Machine and Paper Mill Lubrication appearing in the publication, Lubrication," vols. 35 and 39, July 1949, and March 1953, respectively, published by The Texas Company.

This invention is based on the discovery of a lubricating oil composition which, in addition to possessing the desired performance characteristics, exhibits good demulsibility and high resistance to additive leaching, especially at elevated temperatures. Broadly, the invention relates to the discovery that combinations of barium salts of dialkylhydroxyphenyl sulfides with zinc dialkyldithiophosphates and alkaline earth metal petroleum sulfonates are especially resistant to leaching by water contamination and serve to maintain the desired performance characteristics of the base lubricating oil for extended periods of time under adverse conditions. In addition, the aforesaid additive combination has been found to impart to the lubricating oil base a superior combination of temperature stability and wear-preventing properties.

It becomes, therefore, a primary object of this invention to provide a lubricating composition adaptable to use in paper machines which is extremely resistant to additive leaching and has improved demulsibility properties.

Another object of the invention is to provide an additive combination comprising barium salts of dialkylhydroxyphenyl sulfides, zinc dialkyldithiophosphates and small amounts of calcium or barium petroleum sulfonates which, when carried in a lubricating oil base, is resistant to additive leaching and has enhanced demulsibility properties.

Another object of the invention is to provide a papermachine oil composition which passes the Dynamic Demulsibility Test.

Still another object of the invention is to provide a paper-machine oil composition which possesses a superior combination of temperature stability and wear-preventing properties, as measured by the Four Ball EP Transition Poin and the Wear-Test Temperature Transition Point Tests.

and their mixtures.

A further object of the invention is to provide a method of lubricating machinery adapted to the manufacture of paper using the lubricating compositions herein disclosed.

These and other objects of the invention will be described or become apparent as the description thereof proceeds.

The lubricating compositions of this invention comprise a certain combination of barium dialkylhydroxyphenyl sulfide, zinc dialkyldithiophosphate and calcium petroleum sulfonate. The dialkylhydroxyphenyl sulfide and dithiophosphate salts are commercially available in combination with small percentages of calcium or barium petroleum sulfonates, and are marketed in a concentrated form dissolved in a mineral oil base. The chemical compounds themselves will first be described and reference made to the proprietary compositions used in preparing the present compositions and the various tests conducted 'to show the unusual properties of the combination.

THE BARIUM SALTS OF DIALKYLHYDROXY- PHENYL SULFIDE The barium salts of dialkylhydroxyphenyl sulfides to be used as one of the principal additives of this invention may be represented by the following general formulas:

where R represents an alkyl radical such as isobutyl, tertamyl, hexyl, octyl, dodecyl, propenyl and octenyl. Formula (A) represents basic salts, and formula (B) represemis neutral salts. Also, substituents attached to the benzene nuclei may be in ortho or para position to each other as well as in meta, as shown. Specific examples are the barium salt of ditertiaryamylhydroxylphenyl sulfide and the barium salt of diisobutylhydroxyphenyl sulfide. Such compounds are described in United States Patent 2,379,241 by I. G. McNab.

According to the McNab patent, these. metal salts of aroxysulfides have the property of cooperating with other types of metal compounds, which are corrosive in themselves, to overcome the corrosiveness and enhance the engine performance characteristics of lubricating oil compositions containing same. The corrosive metal compounds include metal derivatives of all types of carboxylic acids, aromatic naphthas or synthetic acids and metal sulfonates. The metals contemplated include aluminum, calcium, nickel, barium, magnesium, cobalt, lead, tin

McNab recommends that the anticorrosive metal salts of aroxy sulfides should be present in lubricating oils in amounts ranging from 0.1 to 2% and preferably about 0.1 to 1%, along with about 0.01 to 2% and generally about 0.1 to 1.0% of the corrosive metal compound. This combination additive is marketed under the trade name of Paranox 65 as a concentrate containing 65% of the metal salts of aroXy sulfides and calcium petroleum sulfonate with 35% of a mineral lubrieating oil. The addend portion of this concentrate con- 't-ains about 80% of the 'metal salt of aroxy sulfide in the and form of the barium salt of diisobutylhydroxylphenyl sulfide and about 20% of calcium petroleum 'sulfonate. This proprietary compound is a known detergent-oxidation in-.

hibitor and as compounded is a viscous liquid having the following typical physical properties: viscosity at 210 F.,

assaesa 4. SUS; flash point, 425 F.; pour point, 10 F.; specific gravity, 60/60, 1.02; and weighs about 8.5 lbs/gal. at 60 F. This material contains about 7.9 weight percent of barium, 0.6 weight percent of calcium, 2.7 weight percent of sulfur, 14.9 weight percent ash, and 15.8 weight percent sulfated ash. It exhibits a 16.7 weight percent carbon residue (Conradson), and a neutralization number (ASTM) of 9 (basic). This material is further described in the publication entitled Enjay-Paramins published by the Enjay Company, Inc. in 1952 on pages 15 and 16 under the proprietary name of Paranox 65.

THE ZINC DIALKYLDITHIOPHOSPHATE The dithiophosphates, as described in United States Patent 2,378,820, Earl Amott, are obtained by the reaction of phosphorus pentasulfide with aliphatic alcohols such as methylcyclohexanol, octyl alcohol or ethylhexyl alcohol. The oil-soluble zinc salts are prepared by reacting the intermediate acidic dithiophosphate with zinc oxide. A preferred product, known commercially as Oronite 262, comprises zinc dialkyl dithiophosphate wherein the alkyl group is a mixture of C -C alkyl radicals obtained from commercial octyl alcohol. This material is a liqud anti-oxidant and anti-wear additive containing 7.7% zinc, 7.2% phosphorus, 14.95 sulfur, and 0.35 calcium. The calcium is present as calcium petroleum sulfonate to act as a solubilizing agent. In the preparation of these materials, one part of phosphorus pentasulfide is reacted with four parts of the commercial octyl alcohol to form a predominance of the dithiophosphoric acid derivative. This material then is reacted with zinc oxide to neutralize the organic acidity. When used in a mineral lubricating oil, the dithiophosphate concentrate is commonly present in an amount ranging from about 0.5 to 1%.

Another material of this type which has also been found to be efiective in the present compositions is zinc dioctyl dithiophosphate containing small amounts of barium petroleum sulfonate known under the trade name of Lubrizol 609. This is a liquid anti-oxidant and antiwear agent having a specific gravity of 1.11 (60/60 F.), and containing 8.32% zinc, 7.62% phosphorus, 15.9% sulfur, and 0.6% barium. The paper machine oil compositions which have been found to exhibit exceptional properties are set forth in the following table:

Table l r Max. and Composition, Percent V Blend I Blend 11 Percent SUS viscosity at 210 F. bright stock. 42. 3 42. 3 Balance. 200 SUB viscosity at 100 F. neutral" 55.4 55.4 Balance. Barium diisobutylhydroxyphenyl sulfide with small amounts of calcium petroleum sulionate (65% cone. in mineral oil carrier 1. 2 1. 2 0. 5-2.0 Zinc dioctyldithiophosphata obtained from commercial octyl alcohol and containing small amounts of calcium petroleum sulionates in a mineral oil (3!1161 1. 1 0. 5-2. 0 Zinc dioctyldithiophosphate containing small amounts of barium petroleum sult'onate in a mineral oil carrier- 1. 1 0. 5-2.0

Table I also gives the range of ingredients that may be used. The amount of alkaline earth metal petroleum sulfonate present in the compositions of this invention will range from about 0.05 to 2.0 weight percent based on the total composition.

In order to further demonstrate the invention, the experimental blends I and 11 set forth in Table I were compared with four difierent competitive oils (designated A, B, C, and D) as to the performance stability and behavior in the presence of water at various temperatures. These results are shown in the following Table II, which gives also the chemical and physical properties of the various samples tested, for comparison:

Table II Competitive Oils Exp'l Compositions Blend A B O D I II Ash as Suli'ate, W Percent 65 0.24 0.40 0.5 0.53.

etals Ba, Ba, Ba, Ba, Ca, Zn.... Be, On, Zn

Acid No.. 1.1 1.1. 0.31 1.66 .77. Base N0 1.6 0.10 0.86 1 11. Phosphorus, W. Percent- 0.0 0.06 0.0 Sulfur, W. Percent 0.36 0.64 0.4 Vis. at 100 F., 451. 592. 651 Vis at 210 F SUS-. 03 68.1 73.8 Viscosity Index. 96.

Carbon Residue, W Percent Demulsibility at 130 F. (Hershel Steam Emulsion N o Navy Emulsion, Min ASTM Rust, Distilled Water- Four Ball EP Transition pt., kg..... Wear Test, Temp. Transition pt., F. Oz Absorption, cc./min

Percent Vis. Inor.

present Percent Entrained Water...-

Percent Water at Draw-ofi-.-

Percent Additive Depletion 28 Dynamic Demulsibility at 180 F.:

Percent Eutrained Water Percent Water at Draw-off...

Percent Additive Depletion. Percent Be... Percent 0a...- Percent Zn 1 Figure includes emulsion at interface.

From Table II it is apparent that the competitive oils containing the combinations of barium and zinc or barium and calcium do not exhibit the same degree of demulsibility with water as do blends I and II which represent this invention. The difference in additive depletion in going from 130 F. to 180 F. is considered to be outstanding, since this problem is a particularly difiicult one at the elevated temperatures. It is to be observed that the competitive oils in each instance showed a tendency to emulsify to a greater extent at 180 F. than they did at 130 F., and, in addition, showed a greater increase in additive depletion. On the other hand, blends I and II of this invention displayed the unusual property of showing an improvement in demulsibility, and additive depletion remained constant in going from tests at 130 F. to 180 F.

The dynamic demulsibility test shown in Table II is a particularly rigorous and significant test developed by one of the inventors herein shown, and is described in copending application, Serial Number 529,552, filed Au- .gust 19, 1955, entitled Dynamic Demulsibility Method and Apparatus under the invcntorship of E. W. Brennan and R. G. Moyer. The full description of the dynamic demulsibility test contained therein is hereby incorporated by reference. According to this copending application, the final criterion of industrial lubricating oils, such as paper machine oils or turbine oils, is the performance under service conditions. It is shown that the Herschel demulsibility test and the steam emulsion test for lubricating oils, known as ASTM D157-51T, do not rate the oils in order of their performance levels, or subsequent commercial service levels. In other words, there is no correlation between the results of the Herschel demulsibility test and the steam emulsion number to the actual demulsibility properties of the oil under the conditions of use in a paper machine or steam turbine. According to this copending application, a dynamic demulsibility test apparatus and method have been developed wherein a given volume of oil sample is continuously circulated from a constant level and constant temperature reservoir into a mixing chamber where it is thoroughly mixed with water under conditions and at a rate which are adjustable to correspond with normal commercial operating or service conditions for the oil, and from which it is returned to the reservoir. The time, temperatures, flow rates, mix ing rates and circulation rates are all adjustable, and same ples may be taken from certain places in the system for determination of the proportions of oil and water present to indicate the ability of the oil to separate from the water. The oil is circulated at rates which provide reservoir residence times the same, or variable within the same limits, as those used in commercial applications of the oil. The water contamination rate is adjusted to provide a relatively severe condition or to simulate the contamination conditions to which the oil will be subjected in commercial applications. These rates, in addition to the temperatures, conditions of mixing and settling, and the length of the test period, will vary in accordance with the particular industrial application for which the oil is formulated, the type of oil, and other factors, such as the amount of water contamination which may be present.

The dynamic demulsibility values will reflect the amount of water taken up by the oil and carried thereby to the parts being lubricated. Dynamic demulsibility values may be determined at various intervals during the test period or only at the end of the test. Comparisons of test results may be made to show any rates of change of demulsibility with time.

Referring to Table II, it is seen that the competitive oils, containing only the two metal component addends in such combinations as Ba and Zn, or Ba and Ca, show additive depletions of from 42 to 86% at 180 F. On the other hand, the present compositions, containing the three-metal-component addend combinations, show additive depletions only of 23 to 34%. Even at F. the dynamic demulsibility results for the present compositions are superior to the competitive oils, especially insofar as the percent water at draw-off is concerned, which is an indication of the amount of pure water separated from the compounded oil. Competitive oil C emulsified to such an extent that a clear indication of the demulsibility properties was not possible.

The experiments demonstrate that the three-component combination of a barium dialkylhydroxyphenyl sulfide, zinc dialkyldithiophosphate and calcium or barium petroleum sulfonate forms a superior paper-machine oil. Although the invention has been illustrated by certain examples the only limitations attaching thereto appear in the appended claims.

What is claimed is:

1. A paper-machine oil composition consisting of a mineral oil base, about 0.5 to 2.0 weight percent of barium diisobutylhydroxyphenyl sulfide, about 0.5 to 2.0 weight percent of zinc dioctyldithiophosphate and about 0.05 to 0.20 weight percent of an alkaline earth metal petroleum sulfonate, said composition being characterized by its ability to pass the dynamic demulsibility test.

2. A paper-machine oil composition in accordance with claim 1 in which the barium diisobutylhydroxyphenyl sultide is present in about 1.2 weight percent concentration.

3. A paper-machine oil composition in accordance with claim 1 in which the zinc dioctyldithiophosphate is present in about 1.2 weight percent concentration.

4. A paper-machine oil composition in accordance with claim 1 in which the alkaline earth metal petroleum sulfonate is calcium petroleum sulfonate.

5. A paper-machine oil composition in accordance with claim 1 in which the alkaline earth metal petroleum sulfonate is barium petroleum sulfonate.

6. A paper-machine oil composition consisting of the following ingredients in weight percent:

SUS viscosity at 210 F. bright stock 42.3 200 SUS viscosity at 100 F. neutral 55.4 Barium diisobutylhydroxyphenyl sulfide with small amounts of calcium petroleum sulfonate (65% come. in mineral oil carrier) 1.2 Zinc dioctyldithiophosphate obtained from commercial octyl alcohol and containing small amounts of calcium petroleum sulfonates in a mineral oil carrier 1.1

said composition being characterized by its ability to pass the dynamic demulsibility test wherein the property of the composition to withstand additive leaching is evaluated under actual conditions of continuous agitation with water followed by continuous settling at temperatures of at least about 180 F.

References Cited in the file of this patent UNITED STATES PATENTS 20 2,344,392 Cook Mar. 14, 1944 2,659,705 Mikeska Nov. 17, 1953 2,824,836 Smith et al Feb. 25, 1958 

1. A PAPER-MACHINE OIL COMPOSITION CONSISTING OF A MEINERAL OIL BASE, ABOUT 0.5 TO 2.0 WEIGHT PERCENT OF BARIUM DIISOBUTYLHYDROXYPHENYL SULFIDE, ABOUT 0.5 TO 2.0 WEIGHT PERCENT OF ZINC DIOCTYLDITHIOPHOSPHATE AND ABOUT 0.05 TO 0.20 WEIGHT PERCENT OF AN ALKALINE EARTH METAL PETROLEUM SULFONATE, SAID COMPOSITION BEING CHARACTERIZED BY ITS ABILITY TO PASS THE DYNAMIC DEMULSIBILITY TEST. 